Conventionally, alkaline storage batteries such as a nickel-cadmium storage battery and a nickel metal hydride storage battery have been used as power sources for a mobile phone, a personal computer, and the like. Further, in recent years, nickel metal hydride storage batteries are used as a power source for a motor of an electric vehicle or a hybrid electric vehicle. Positive electrodes of such alkaline storage batteries broadly are classified into sintered positive electrodes and non-sintered positive electrodes. In the non-sintered positive electrodes, a conductive core material that is made of nickel or nickel-plated steel has been used.
However, such a core material may include a metal (such as copper) other than nickel or iron as an impurity. When a large amount of impurity is included, the impurity dissolved in an electrolyte solution from the core material is deposited and the deposited metal may develop a minute short circuit in positive and negative electrodes.